It's an interesting idea - compiling a library of obsolete sounds, things you don't hear anymore. It's a collection put together by an entity known as Cities and Memory, involving some 1,000 artists amassing an aural library of disappearing noises. 

There are the things you might expect - like typewriters, a VHS tape being put into a VCR, a modem dialup, a projector starting up as the film winds through the machine and similar once familiar sounds from years gone by. But then I came across one I wasn't entirely expecting - tuning across an analogue radio dial. I'm not sure I would label that "obsolete" just yet, until I realized that the guy who submitted it lives in England, where everything is now digital. So to him, that would be out of date. 

There are few others that are somewhat more questionable. The sound of a light switch is obsolete? A hand mixer? Someone turning on a fan? I'm not sure those are passé just yet. 

Still, it's stunning to think the sounds we once took for granted are now considered by many to be echoes of the past.

You can hear his contribution and the rest of the 'obsolete' audio here.